Slater started in center field and went 1-for-3 in Wednesday's 6-5 loss to Colorado.
Slater made his first appearance as a member of the team after Cincinnati acquired him from the Giants on Sunday. He could be a regular in the lineup heading into the All-Star break and shortly thereafter. Reds manager David Bell said TJ Friedl (hamstring) could rejoin the team 7-to-10 days after the break.